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Sharp QT-8B

Brand: Sharp.
Model: QT-8B.
Origin: Japan.
Introduction: 1970.
Type: Early basic portable calculator..
Functions: 4-Basic function, no memory and no constant. Operates with AC power and batteries for portability..
Display: 8 digit + Sign individual VFD Itron tubes..
Keyboard: 15 reed-switch keys and ON/OFF switch.
Main chips: Rockwell NRD2256, DC2266, AC2261, AU2271. All with datecode 7032, except AU2271 with datecode 7033, around July 1970..
Logic comments: This is the battery-operated version of the Sharp QT-8D with the first LSI CMOS technology architecture used in an electronic calculator. It uses 4 chips manufactured by Rockwell in the USA but designed by Sharp, each counting around 1875 electronic components (now you can see more than 50,000,000 components on the same surface!). This architecture, with some changes, was used in other calculators like Sharp EL-8, EL-8M, EL-160, Burroughs C3260 and other OEM versions. Keyboard has an unusual layout and was reduced to a minimun key count: only 15 keys for all functions, including number input. A brief description of each key:

0-9 and . (decimal point): Numerals and decimal point keys. All this keys have an automatic locking system to avoid pressing more than one key at a time.

(Multiply-Divide): Use to multiply or divide if you complete the operation with += or -= respectively, see examples below.

+= (Add-Multiply): Use to add or complete a multiplication.

-= (Substract-Divide): Use to subtract or complete a division.

C (Clear): Clears the calculator.

Simple operation examples:
a) To compute 2+3 enter 2
+= 3 +=
b) To compute 2-3 enter 2
+= 3 -=
c) To compute 2*3 enter 2
3 +=
d) To compute 2/3 enter 2
3 -=
Remarks: This calc is a portable version of the Sharp QT-8D. The main power circuit is replaced by a battery pack with 6 rechargeable 1.25v cells. Now the power circuit is included in the external big base QTA-2. Batteries may be recharged during normal operation of the calculator or when is power off..
Size: Calculator: 9.65 x 5.19 x 2.75 in, 245 x 130 x 70 mm.
AC Adapter QTA-2: 11.30 x 4.92 x 2.68 in, 287 x 125 x 68 mm..
Accesories: AC Adapter and base QTA-2, dust cover and instruction manual, all in very acceptable condition!.
Condition: (8/10) Very good, working.
Download: Original Instruction Manual of the Sharp QT-8B. English, PDF format, Download.
Additional readings: You can read a complete article about the Sharp QT-8B here, from


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